Pulp hydrator



, tively little rubbing action of *y ANDREW MUIRH-EAD,

Patented Mar. 16, 1926.

UNITED STATES 0F HAVERHILL, MASSACHUSETTS, AD `IEIVIEIREYIT'E K. 'MANS- FIELD, OF WHITE PLAINS, NEW YORK.

PULP HYDRATOB.

Application led December 30, 1925.

T0 all whom t may concern.'

Be it known that we, ANDREW MUIHHEAD of Haverhill', county of Essex, State of Massachusetts, and EvEnnT'r K. MANSFTELD, of White Plains, county of Westchester, State of New York, citizens of the United States, have invented an Improvement in Pulp Hydrators, of lwhich the following is a specification.

In the process of preparation of chemical pulp for the paper machine, the operation of hydrating and defelting ground wood, paper and other cellulose fibrous material has vusually, or almost universally been performed in the pulp beater.

As the primary purpose of this operation is to cause the fibers to be separated and chemically united with water, no beating or grinding action, which forcibly tears apart the fibers is necessary, so that, in order to avoid as much as possible, the cutting of the fibers by the beater roll, the roll is run at a substantial distance above the bed, and, to a large extent merely acts as a circulating pump', hat is, the hydrating process is, to a large degree effected, and may, practically be entirely effected, by the rubbing action of the fibers on each other as they are circulated. Consequently, the greater the relative motion or rubbing action of'the fibers as the pulp is circulated, the greater will be the hydrating and defelting action.

In the pulp beater, while some relative movement of fibers on each other is caused by the flow of the pulp about the channel of the beater, yet this flew is very sluggish, largely due to the fact that the roll cannot be rotated above a certain speed without throwing the pulp back over itself, and there is normally but little relative movement of the fibers, for, unless disturbed by other means than the roll, the fibers tend to remain in practically the same relative position during nearly the whole of the travel about the Vat, so that, normally, comparathe fibers on each other takes place. Moreover, it is well known that the chief objection to the use of the. beater for this purpose is the lack of uniformity of its action on the pulp, due to the fact that the pulp nearest the mid-feather normally travels under the roll more frequently than that nearest the sides. Another important objection to the use of the beater for hydrating purposes is circulatory K and so Serial No. 78,498.

the slow speed at which the operation is performed, also, while the roll is usually operated at some distance from the bed to avoid cutting the fibers, yet, in practice, even under these conditions the blades of the roll haveau undesirable cutting effect.

The objects of our invention are to pro vide an improved appartus for hydrating and separating cellulose fibers, where me chanical action in tearing apart the fibers is unnecessary, in whichthe extent of the relative. motion or rubbing action of they fibers, or portions of the mass, on each other will be greatly increased, as compared with the action in the ordinary beater, and the speed of circulation and relative motion will be greatly accelerated, so that the timeprequired foi` the required hydrating and felting action will be greatly reduced, and in which the liability that the fibers Will becut during the operation will be entirely obviated.

We accomplish these objects, primarily, by-providing a completely enclosed iuid system, in which the circulating agent is preferably a suitablel form of centrifugal pump, and in which the form and cross sectional area ofthe circulatory passages are so varied that the velocity of the pulp at different portions of the circuit is constantly being varied by means of reverse and accelerated currents, and currents which are variably reduced in speed at different points in the travel through the circuit, so that relative displacement of the fibers is constantly taking place throughoutthe entire mass and is taking place at a high speed in certain portions, and rapidly in other portions, as compared with prior practice, that the entire mass will be operated on with practically perfect uniformity.

For a more complete understanding of our invention, reference is made tothe accompanying drawing in which:

Fig. 1 is a side elevation of a preferred embodiment of the invention.

Fig. 2 is an end view thereof and Fig. 3 is a sectional view at line m-x of Fig. 2.

In providing means for causing circulation of the pulp through the circuit hereafter more specifically described, a pair .of centrifugal pumps 2 and 4: of well known form are preferably employed, although other types of rotary pumps may also be effectively employed, and in which the impeller comprises a series of rearwardly curved blades 5.

According to our invention, an upright discharge pipe 6 and 8 is extended from the discharge port of each pump to a height suficient to give the head necessary to secure efficient operation, each being connected to an elbow section 7 and 9, so that the discharge therefrom will be approximately horizontal.

A pair of tubular casings, forming mixing and' circulation chambers, are rovided, which comprise funnel shaped hea sections 10 and 12, central o enings in the ends of which are respective y connected to the discharge ends of the pipe elbows 7 and 9, intermediate cylindrical sections 13 and 15, to which the base ends of the head sections tail sections .16 and 18,

sections 13, are, in turn, connected, by pipe elbow sections 17 and 19, to the inlet ports of the pumps 4 and 2 respectivey. The internal diameters of the intermediate sections are somewhat more than twice and preferably nearly three times as great `as the internal diameters of the discharge the pumps, and the tail sections 16, 18 taper in diameter from the full diameter of the intermediate sections A pipes to the pumps,.said pipes being of approximately the same diameter. The casing sections are also arranged to decline from the level of the discharge ends of the elbows 7, 9, the extent to which they decline being preferably suiiicient to cause a substantial acceleration in the flow, so that the whole circuit may be readily drained through dump pipes 20, 22 which are connected to the-bases of the vertical discharge pipes 6,

he tapering tail sections are also formed so that the bottom portions thereof extend at the inclination of, and continuously with the bottom portions of the intermediate sections, so that, when th practically all the pulp may be readily i washed therefrom. The construction is also such that there will be no dead spaces in which the pulp does not circulate, as the operation is being performed.V

Vertical filling pipes 24, 26 are connected to the upper portion of each head section 10, 12, covers 25, 27 being provided for closing the same, and balli provided in said head sections, which extend upwardly from the upper ortions of the inlet ports, to which the el ow sections 7, 9 are connected, in a 90 curve and then vertically into the filling pipes to points at a suitable distance from the covers25, 27. i In operating the apparatus, the whole circuit will be completely lled with water and a suitable quantity of somewhat disine circuit is drained, A

e plates 28, 30 are 1 tegrated ground wood, paper, or other cellulose iberous material, and the covers 25, 27 will be closed. The pumps will be operated at a suitable speed, so that the material will be forced up the discharge and into the relatively large through the saine to the intake side ot' the pumps, the arrangement being such that the material will pass through one pump and the directly connected circulation pipes and chambers and then through the other pump and chambers lin order. yAs the material, or stuff is forced into thel head section of each chamber 13, 15, the effect will be similar to that of a jet discharged under the surface of a substantially larger body of water, that is, the force of the jet will be dissipated in of the jet will e completely dissipated depends on various the `jet at its point of delivery to the casing and the consistency of the charge, and is such that it will cause acceleration throughout at least half the length he material passes into the tapering tailsections, acceleration in flow material will be carried, will cause relative on each other,

ydrating action will be.rapidlv carried on. In addition to the diverse currents which will thus be lmade to flow in the casing, the baille plates 28, 30 will appreciably Iincrease the complexity' of the circulation by. intercause a down flow in the remaining portion, which will meet the return flow in t e upper portion of the chamber caused by t e projection of the Jet therein, as previly described. The baille plates also prevent lodgment of the stuff in the filling pipes, the circulation therein being as active as in other portions of the system.

When the material has been circulated for -liminary to the hydrating a sufficient length of time to complete the operation, the dump pipes will be opened, so that the material `may be discharged and all pulp may be readily Washed from the pipes and casings and then they may be refilled and the operation repeated, the pumps being continuously operated at all times.

I The above described apparatus is considered to have numerous advantages over the ordinary beater, primarily because the action on the material is uniform and the hydrating operation is. performed much lnore rapidly thanin an ordinary beater, and also because it does not cut the fibers.

The apparatus is primarily useful, in practice, as a secondary beater, as it is-often considered desirable to circulate the stock in an ordinary beater until it is thoroughly broken up and mixed with Water,.as a preoperation. In many instances, however, the stock will be sufficiently disintegrated by passing it thru a shredder before delivering it to the above described apparatus.

We'claim:

1. Apulp hydrator comprising a pump having inlet and discharge pipes connected thereto andan elongated tubular casing of substantially greater transverse area than the area of said pipes and connected at its ends to said pipes, respectively, to form a closed fluid circuit through which the fluid may be circulated by said pump, said discharge pipe from the pump being arranged to project a 4jet into said casing longitudinally thereof.`

2. A pulp hydrator comprising a rotary pump having an inlet and a discharge pipe "of uniform transverse area connected thereto, an elongated tubular casing of substantially greater transverse area than that of said pipes and having said inlet pipe connected-thereto at one end and said discharge pipe connected to the opposite end, to form a closed fluid circuit, the portions .of said casing at each end being formed to taper to said pipes, respectively, to prevent lodgment of the material therein as it is circulated.

3. A pulp hydrator comprising a rotary pump having inlet and discharge pipes of uniform area connected thereto, an elongated tubular casing of substantially greater pipes, said discharge pipe being connected to one end of saidn casingl in position to deliver a jet thereto longitudinally ofthe middle thereof, andsaid inlet pipe being connected to the opposite end of said casing to form a closed fluid circuit. 4

4. A pulp hydrator comprising a rotary pump having inlet-and discharge pi es of uniformftransverse area, an elongate g tubular casing of substantially greater tranlsverse area than that of said pipes, and having its transverse area than that of said` p having an inlet port end portions tapering to openings corresponding in size to the passageways in said pipes and to which. said pipes are respectively connected to form aclosed fluid circuit, said discharge pipe being arranged at the point of connection with said casing in position to direct a jet longitudinally of the middle of said casing.

5. A pulp hydrator comprising a rotary pump having inlet and discharge pipes of uniform transverse area, an elongated tubular casing of substantially greater transverse area than that of said pipes, and having its end portions tapering to openings corresponding in size to the passagcways in said pipes and to Which said pipesl are respectively connected to form a closed fluid circuit, said casing being arranged to extend horizontally and said discharge pipe being arranged to extend upwardly and then horizontally at the point of connection with said casing, in position to direct a jet longitudinally of the middle thereof and the bottom of said casing being arranged to decline from one of said openings to the other.

6. A pulp hydrator comprising a centrifugal pump having a discharge pipe extending upwardly therefrom and having a horizontally extending end portion, a horizontally disposed elongated tubular casing having an inlet port at one `end of relatively smaller area than the transverse area of the casing, said end portion of said discharge pipe being connected vto said port and arranged to deliver a jet to said casing longitudinally of the middle thereof 'and a return pipe connecting the opposite end of said casing and the inlet to the pump.

7. A pulp hydrator comprising a centrifugal pump having a discharge pipe extending upwardly therefrom and having a horizontally extending end portion, a horizontally disposed elongated tubular casing 110 having an inlet port at one end of relatively smaller area than the transverse area of the casing, said end portion of said discharge pipe being connected to said port and arranged to deliver a jet to said casing longi- 115 tudinally of the middle thereof, a filling pipe. opening to the upper side of said casing adjacent said port and extending upwardly therefrom, means for closing the upper end of said filling pipe, means 120 arranged to deflect a portion of' the jet into the upper portion of said filling pipe and a return pipe connecting the opposite end of said casing and the inlet to said pump.

8. A pulp hydrator comprising a centrifugal pump having a discharge-pipe eX- 1 tending upwardly therefrom and having a horizontally extending end portion, a horizontally disposed elongated tubular casing 130 at one end of relatively smaller area than the transverse ereaof the casing, said end portion of said discharge pipe beingronnected to said port and ar ranged to deliver :L jet to seid casing longitudinally of the middle thereof, :t filling pipe opening to the 'upper side of Seid Casingl edjaeent Seid port and extendingT upwardly therefrom` means for closing the upper end of seid filling,` pipe, a Curved bafiie plete extending horizontally from seid inlet port and upwardly into Said filling pipe in position to deflect a, portion of the .Jet into the upper portion' *thereof and to cause a circulation upwardly and downwardly therein and the opposite end of to the pump.

In testimony whereof, we have signed our names toy this specification.

ANDREW MUIRHEAD. EVERETT K. MANSFIELD.

said casing and the inlet a ,return pipe eonneoting 15 

